Commercially available silver halide color photographic materials and associated image forming methods therewith have diverse applications over a wide range of technologies. The capabilities required from these known light-sensitive materials are varied according to the respective applications of the light-sensitive materials, and one such capability is a high density recording property. In order to demonstrate a satisfactory high density recording property in a silver halide color photographic material, high sharpness must be provided. Accordingly, various conventional techniques for increasing the sharpness have been developed and implemented according to the degree of the sharpness requirement for the respective light-sensitive materials.
It is known that halation causes a lowering in sharpness in a light-sensitive material. Two causes of such halation primarily originate from a reflection of incident light at an interface between an emulsion layer and a support or a support and air, and inadvertent irradiation from scattered light attributable to the silver halide grains themselves.
It has been found effective to prevent such deterioration of sharpness by halation to provide a layer containing a white pigment on a support, such as described in, for example, JP-B-58-43734 (the term "JP-B" as used herein means an examined Japanese patent publication), and JP-A-58-17433 (the term "JP-A" as used herein means an unexamined published Japanese patent application), JP-A-58-14830 and JP-A-61-259246. However, problems have been encountered in that the incorporation of white pigment to such an extent as needed to sufficiently improve or preserve optimal sharpness deteriorates the physical strength of the pigment containing layer against so-called folding and that it thus becomes difficult to maintain the smoothness of the layer containing white pigment.
Further, other known methods for improving sharpness include coloring a component layer of a photographic material with a dye, which is described in, for example, U.S. Pat. Nos. 2,548,564 and 3,625,694, JP-A-56-12639 and JP-A-63-197943, European Patent 0337490A2, and JP-A-1-188850. However, it has been found that the increase in content of a dye used for improving sharpness increases white background stain after processing, which makes it impossible to increase an added amount of a dye to such an extent as needed so that the sharpness is sufficiently improved. Stain of a background in a silver halide color photographic material is not commercially acceptable since it not only affects the quality of the background of an image but it also causes color stain in a color image and deteriorates visual sharpness. Particularly, in the case of a reflection type light-sensitive material, the presence of stain is a very important consideration since a reflection density of the stain is theoretically magnified several times by the magnitude of the transmission density and, therefore, even slight stain noticeably deteriorates an image quality.
Meanwhile, a characteristic ever-increasingly required for silver halide color photographic material is amenability to more rapid processing. It is conventionally thought that the silver chloride content of an emulsion is increased for the purpose of improving a rapid processing property. The methods in which an emulsion having a high silver chloride content is used are widely described in, for example, JP-A-58-95345, JP-A-59-232342 and JP-A-60-19140. Also, in the commercial market, emulsions used in color photographic paper are actually going toward and adopting the usage of a higher silver chloride content. A specific absorption range of this high silver chloride emulsion resides in a short wavelength range and has to be subjected to a spectral sensitization in order to absorb a visible ray of a longer wavelength and/or an infrared ray as well for sensitization.
In such a high silver chloride emulsion, however, the problem arises that even if one tries to subject the emulsion to a spectral sensitization with a sensitizing dye ordinarily used for a silver halide emulsion primarily comprising silver bromide, that it is generally difficult to sensitize only to a ray of a specific wavelength.
In efforts to solve this problem, it has already been discovered by the present inventors that a rapid processing property and a sharpness of a silver halide color photographic material can be improved by providing a spectral sensitization with a spectral sensitizing dye which forms a J-aggregate in a high silver chloride emulsion to particularly establish an absorption peak of a certain long wavelength ray in a red spectral sensitization wavelength region (such the absorption peak provided by J-aggregate is called J-band). Meanwhile, it was necessary to develop a technique capable of treating a spectral sensitizing dye added to a high silver chloride emulsion so as to more effectively form the J-aggregate.